Laser-induced liquid metal infiltration of beryllium oxide ceramic substrates

Abstract

The application belongs to the technical field of laser processing, and specifically provides a laser-induced liquid metal infiltration beryllium oxide ceramic substrate augmentation method. The high-temperature instantaneous heating effect of a picosecond laser is used to cut the surface oxide layer of the liquid metal and eliminate its binding to the liquid metal. The nonlinear resonance phenomenon induced by the laser is used to guide the directional flow of the liquid metal along the preset direction and make it preferentially infiltrate into the micro-cracks and defect areas on the surface of the substrate. At the same time, the continuous action of the picosecond laser effectively inhibits the regeneration of the surface oxide layer of the liquid metal. Through the synergistic effect of dynamic rupture and nonlinear resonance, the liquid metal infiltration behavior is improved, the accuracy and uniformity of the liquid metal flow on the structured workpiece surface are improved, and reliable performance guarantee is provided for precision augmentation and repair applications.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and to a method for supplementing beryllium oxide ceramic substrates by laser-induced liquid metal wetting. Background Technology

[0002] Liquid metals, especially gallium-based liquid metals, are widely used in flexible electronic devices, thermal management, sensors, and material repair due to their low melting point, high thermal conductivity, high electrical conductivity, and good flow properties. For beryllium oxide ceramic substrates used in attenuators, microcracks and localized defects are prone to occur during subsequent processing or service. Liquid metal wetting can repair the surface and improve thermal conductivity. Furthermore, liquid metals can form a lubricating film, reducing friction between the tool and workpiece, lowering wear rates, extending tool life, and improving grinding efficiency. Simultaneously, the lubricating effect of liquid metals helps improve surface quality, reduce scratches and surface defects, and enhance the finish of the final product. By controlling grinding temperature and reducing cutting forces, the introduction of liquid metals can also improve processing stability and reduce energy consumption. Therefore, the use of liquid metal wetting technology not only optimizes the grinding process but also significantly improves the overall performance and reliability of products, meeting the high precision and high efficiency demands of modern manufacturing.

[0003] Traditional liquid metal coating methods suffer from numerous drawbacks in practical applications, limiting their widespread use. First, the coating process typically requires high-temperature heating, which not only increases energy consumption but can also lead to thermal deformation or damage to the substrate, affecting its performance. Second, traditional methods are highly sensitive to the coating environment, easily affected by air humidity and oxidation, resulting in unstable coating quality and even defects such as bubbles and cracks. Furthermore, poor coating uniformity makes it difficult to achieve complete coverage of complex-shaped workpieces, thus affecting lubrication and protective performance. Moreover, traditional liquid metal coatings often have insufficient adhesion, easily peeling off, leading to short service life and high maintenance costs. Finally, the selection of coating materials is limited, failing to meet specific application requirements. Therefore, there is an urgent need to explore new coating technologies to overcome the limitations of traditional methods and improve the reliability and applicability of liquid metal coating.

[0004] In recent years, laser processing technology has been widely applied in materials science. Picosecond lasers, in particular, with their extremely short pulse widths and high peak power, can generate instantaneous high temperatures and pressures on material surfaces, enabling rapid and uniform heating of liquid metals during coating, thus achieving better fluidity and wettability. This precise heating method not only improves coating adhesion but also effectively reduces internal defects such as bubbles and cracks, thereby enhancing the overall quality of the coating. Laser-assisted coating is a relatively gentle process that can be performed at lower temperatures, avoiding thermal damage to the substrate, making it particularly suitable for coating heat-sensitive materials. The high energy density of lasers allows for localized heating, enabling precise coating of complex shapes and small parts, broadening the range of applications. Laser-assisted liquid metal coating processes offer high production efficiency and environmental friendliness, reducing the waste and pollution that may be generated in traditional coating methods.

[0005] Existing methods for improving the wettability of liquid metals have several limitations. First, chemical treatments typically involve corrosive agents, which may damage the substrate and affect its long-term stability and performance. Furthermore, the effects of chemical treatments are difficult to control, potentially leading to uneven improvement in wettability. Second, physical modification methods, such as surface roughening, while improving the wettability of liquid metals, often struggle to achieve precise control over the microstructure and may increase manufacturing costs. Third, traditional laser processing techniques, while removing the oxide layer, struggle to effectively guide the flow of liquid metal, resulting in limited improvement in wettability. In particular, during attenuator manufacturing, beryllium oxide ceramic substrates are prone to microcracks and defects, severely impacting heat dissipation and reliability. Existing liquid metal coating and laser processing methods cannot simultaneously meet the requirements of oxide layer removal, microcrack filling, and directional flow control. Summary of the Invention

[0006] To address the technical problems in the prior art, this invention provides a laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates, comprising the following steps: S1. Fix the workpiece to be processed on the fixed component of the dynamic temperature control system and set the heating temperature to 35℃~50℃. S2. The liquid metal in the storage pump is evenly sprayed onto the surface of the workpiece through a high-pressure constant flow nozzle to form a uniform and continuous liquid metal coating layer. S3. Activate the laser modulator to control the laser beam to act on the liquid metal coating layer. Set the laser parameters to cause local rupture of the oxide film on the surface of the liquid metal. At the same time, the interaction between the laser and the liquid metal interface induces nonlinear vibration at the liquid metal interface, causing the liquid metal to diffuse directionally along the workpiece surface and gradually wet into the defect area on the workpiece surface, thereby achieving wetting and repair. S4. During the spraying and laser processing, the fixed component is used to collect the excess liquid metal that does not adhere to the surface of the workpiece during the processing, and the recycling component is used to make it flow back to the storage pump to achieve recycling.

[0007] Furthermore, in step S1, the fixing assembly includes a coarse filter membrane and a fine filter membrane. The workpiece is fixedly installed on the coarse filter membrane by a clamp. The fine filter membrane is located below the filter membrane assembly. The temperature of both the coarse and fine filter membranes is regulated by a main control controller, a temperature control switch, and a temperature controller.

[0008] Furthermore, in step S2, the high-pressure flow-stabilizing nozzle includes an air pump, a movable chamber, a high-pressure chamber, a low-pressure chamber, and a flow stabilizer arranged sequentially. The air pump is connected to the movable chamber via an injection pump. A pressure piston is slidably disposed between the movable chamber and the high-pressure chamber. The liquid storage pump is connected to the high-pressure chamber via an infusion switch. The high-pressure chamber and the low-pressure chamber are connected via an movable switch. The low-pressure chamber is connected to the flow stabilizer via a multi-channel nozzle. The injection pump, the infusion switch, and the movable switch are all connected to the main control unit.

[0009] Furthermore, when the liquid metal enters the low-pressure chamber, it undergoes initial rectification through the turbulence suppression grid at the inlet; when flowing through the high-pressure chamber, it reduces fluid resistance with the help of the nanoscale hydrophobic coating on its inner wall; finally, it is stably ejected in a laminar flow manner through the multi-channel nozzle in the active chamber.

[0010] Furthermore, in step S4, the coarse filter membrane has a pore size of 50μm-100μm, the fine filter membrane has a pore size of 5μm-10μm, and the surface is provided with an oleophobic and hydrophilic coating.

[0011] Furthermore, in step S4, the recovery assembly includes a recovery chamber, a recovery pipe, and a recovery room. The top of the recovery chamber is connected to a fine filter screen, and the bottom is connected to the recovery room through the recovery pipe. The recovery room is connected to a liquid storage pump.

[0012] Furthermore, the inner wall of the recycling pipe is provided with a spiral guide groove, and the outer wall is provided with a heating layer.

[0013] Furthermore, after the liquid metal is sprayed onto the workpiece, the coating detection device emits a detection beam towards the workpiece surface and receives the reflected light signal to determine the location of unevenness in the liquid metal coating. The coating detection device converts the unevenness location information into an electrical signal and feeds it back to the laser modulator, so that the laser system is precisely aligned with the area. The nonlinear resonance effect generated by the laser guides the flow of the liquid metal, thereby achieving a smooth coating on the workpiece surface.

[0014] Furthermore, the liquid metal is liquid gallium, and the purity of the liquid gallium is not less than 99%.

[0015] Beneficial effects: 1. In this invention, by setting up a laser modulator, the nonlinear resonance driving force of the interface induced by picosecond laser and the capillary force can be organically combined, and the rheological and viscous resistance of the solid-liquid interface can be dynamically controlled. This allows for precise guidance of liquid metal to penetrate and diffuse into the microcracks and deep defects on the workpiece surface in a directional and non-destructive manner, completely eliminating cavitation bubbles and diffuse porosity defects inside the reinforcement layer. This process method completely solves the problem of difficult filling of microcracks on the surface of the attenuator ceramic substrate, significantly improving the filling tightness and interfacial bonding strength inside the cracks. At the same time, while transiently physical ablation of the dense oxide film, it effectively interferes with and inhibits the thermodynamic secondary oxidation of the molten fluid surface, significantly extending the rheological time window of the active fluid, thereby completely eradicating the common problem of flow field stagnation caused by rapid regeneration of local oxide layers.

[0016] 2. In this invention, by setting up a coarse filter membrane, a fine filter membrane, a main control unit, a temperature control switch, and a temperature controller, it is possible to filter and remove impurities from unattached liquid metal and debris, so that the pure liquid metal remains in a molten state and permeates into the membrane, facilitating subsequent recycling.

[0017] 3. In this invention, the spiral guide channel can guide the liquid metal to flow in a swirling motion, reducing adhesion to the wall surface. Combined with the heating layer, heat loss can be reduced, and the liquid metal can be prevented from solidifying during the recycling process.

[0018] 4. In this invention, by setting up a coating detection device, the unevenness of the liquid metal coating layer can be detected in real time and feedback can be provided to improve the uniformity of coating. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall installation structure of the present invention; Figure 2 This is a schematic diagram illustrating the principle of laser-induced nonlinear resonance in liquid gallium metal according to the present invention. Figure 3 This is a schematic diagram of the installation structure of the high-pressure flow-stabilizing nozzle of the present invention; Explanation of reference numerals in the attached figures: 1. Current controller; 2. Coating detection device; 3. Temperature controller; 4. Temperature control switch; 6. Main control controller; 7. Recovery pipeline; 8. Recovery chamber; 9. Fine filter membrane; 10. Coarse filter membrane; 11. High-pressure constant flow nozzle; 12. Air pump; 13. Recovery chamber; 15. Liquid storage pump; 17. Laser regulator; 18. Laser lens; 19. Fiber optic cable; 20. Focusing lens; 22. Workpiece; 23. Infusion switch; 24. Injection pump; 25. Pressure piston; 26. High-pressure chamber; 27. Liquid gallium metal; 28. Low-pressure chamber; 29. ​​Flow stabilizer; 30. Discharge switch; 31. Multi-channel nozzle; 32. Movable switch; 33. Movable chamber. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0022] This invention provides a laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates, such as... Figure 1 , Figure 2 and Figure 3 As shown, the specific steps are as follows: S1. Place the beryllium oxide ceramic substrate workpiece 22 for the attenuator on the coarse filter membrane 10 in the fixing assembly, and fix the workpiece 22 at the center position of the coarse filter membrane 10 by the clamp; then control the current controller 1 and temperature controller 3 to turn on by the main controller 6, and turn on the temperature control switch 4 of the coarse filter membrane 10 and the fine filter membrane 9, and set the heating temperature to 35℃~50℃ to keep the liquid metal in a flowing state.

[0023] S2. The liquid metal in the storage pump 15 is uniformly sprayed onto the surface of the workpiece 22 through the high-pressure constant flow nozzle 11 to form a uniform and continuous liquid metal coating layer. The high-pressure constant flow nozzle 11 includes an air pump 12, a movable chamber 33, a high-pressure chamber 26, a low-pressure chamber 28, and a flow stabilizer 29 arranged in sequence. The air pump 12 is connected to the movable chamber 33 through an injection pump 24. A pressure piston 25 is slidably disposed between the movable chamber 33 and the high-pressure chamber 26. The storage pump 15 is connected to the high-pressure chamber 26 through a liquid infusion switch 23. The high-pressure chamber 26 and the low-pressure chamber 28 are connected through a movable switch. The low-pressure chamber 28 is connected to the flow stabilizer 29 via the multi-channel nozzle 31. The injection pump 24, infusion switch 23, and movable switch 32 are all connected to the main control unit 6. Specifically, the injection pump 24 is turned on, allowing the compressed air in the air pump 12 to enter the movable chamber 33, which pushes the pressure piston 25 to compress the liquid metal in the high-pressure chamber 26 and bring it into the low-pressure chamber 28. When flowing through the high-pressure chamber 26, the fluid resistance is reduced by the nanoscale hydrophobic coating on its inner wall. At the inlet of the low-pressure chamber 28, the flow is initially rectified by the turbulence suppression grid, eliminating large-scale flow turbulence. Under high pressure, liquid metal enters the flow stabilizer 29 through the multi-channel nozzle 31. The multi-channel nozzle 31 transforms the liquid metal from a potentially residual turbulent flow into a stable laminar flow state, allowing it to be ejected at a uniform speed and precise flow rate. This achieves a high initial velocity while significantly reducing the unevenness and fluctuations in the spray. The low-pressure chamber 28 is also connected to the recovery chamber 13 via the liquid outlet switch 30. This configuration enables the effective cleaning of any residual liquid metal in the low-pressure chamber 28.

[0024] S3. Turn off the syringe pump 24, infusion switch 23, and dispensing switch 30. Start the laser regulator 17, which connects to the laser lens 18 and focusing lens 20 via PWM signal pulse width modulation. Both the laser lens 18 and focusing lens 20 are connected to optical fibers 19. By adjusting the duty cycle of the PWM signal, precise control of the laser output energy and pulse frequency is achieved. After being focused sequentially by the laser lens 18, optical fiber 19, and focusing lens 20, the laser acts on the liquid metal coating layer on the surface of the workpiece 22. The preferred laser parameters are as follows: pulse width 1ps to 100ps, power 5W to 100W, and scanning speed 50mm / s to 500mm / s. The laser processes the surface of the workpiece 22 using a spiral filling path, starting from the center of the workpiece 22.

[0025] When the picosecond laser is applied to the liquid metal coating, the high-energy photons instantly cut through the oxide film on the liquid metal surface, exposing the pure liquid metal inside, specifically liquid gallium-27 with a purity of no less than 99%. Simultaneously, the internal liquid gallium-27 absorbs the laser energy and ionizes, with electrons escaping from the atoms to form free electrons and ions, thus generating plasma. This plasma has extremely high temperature and pressure and rapidly expands into the surrounding space. During this expansion, an interaction force is generated between the plasma and the liquid gallium-27: the outward expansion of the plasma exerts a reaction force on the liquid gallium-27, causing deformation and vibration on its surface. Due to the complex interactions of multiple physical processes involved in the plasma expansion process, the resulting vibration exhibits typical nonlinear characteristics. This nonlinear resonance effect can effectively reduce the flow resistance of the liquid gallium-27 and guide its movement in a specific direction.

[0026] After the oxide film on the surface of liquid gallium 27 is damaged, the internal liquid gallium 27 diffuses directionally under the combined action of capillary force and nonlinear vibration driving force, and penetrates into the microcracks and defect areas on the surface of workpiece 22 until it is uniformly wetted throughout the entire surface of workpiece 22. This process improves the uniformity of wetting of liquid gallium 27 on the surface of beryllium oxide ceramic substrate and the interfacial bonding strength.

[0027] S4. Liquid gallium 27 that failed to adhere to the surface of workpiece 22, as well as liquid gallium 27 and workpiece 22 particles that fell off during processing, first pass through a coarse filter membrane 10 to filter out larger workpiece 22 particles, and then through a fine filter membrane 9 to filter out smaller workpiece 22 particles. During the process of passing through the two membranes, because the membrane temperature is higher than the melting point of gallium, the liquid gallium 27 remains liquid and permeates to the other side into the recovery chamber 8, while impurities that cannot pass through the membranes remain on the membranes. Finally, it flows back to the storage pump 15 through the recovery pipe 7 and the recovery chamber 13. The inner wall of the recovery pipe 7 is provided with a spiral guide groove to guide the liquid gallium 27 to swirl and reduce wall adhesion; the outer wall of the recovery pipe 7 is covered with a heating layer to reduce heat loss.

[0028] The syringe pump 24, infusion switch 23, movable switch 32, and dispensing switch 30 are controlled cyclically according to a preset timing sequence to achieve periodic generation of pulse pressure waves, thereby improving the stability of liquid metal delivery.

[0029] like Figure 1 and Figure 2As shown, when the laser acts on the liquid metal coating, a closed-loop feedback control step is added to the coating detection device 2: the coating detection device 2 emits a detection beam to the surface of the workpiece 22 and receives the reflected light signal to identify uneven areas of the liquid metal coating; then the uneven position information is converted into an electrical signal and fed back to the laser regulator 17; the laser regulator 17, based on the feedback signal, uses the nonlinear resonance effect induced by the picosecond laser to precisely guide the flow of the liquid metal, thereby achieving a smooth coating of the area.

[0030] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0031] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for supplementing a beryllium oxide ceramic substrate by laser-induced liquid metal wetting, characterized in that, Includes the following steps: S1. Fix the workpiece (22) to be processed on the fixed component of the dynamic temperature control system and set the heating temperature to 35℃~50℃; S2. The liquid metal in the storage pump (15) is uniformly sprayed onto the surface of the workpiece (22) through the high-pressure constant flow nozzle (11) to form a uniform and continuous liquid metal coating layer. S3. Start the laser modulator (17) to control the laser beam to act on the liquid metal coating layer, set the laser parameters to cause local rupture of the oxide film on the surface of the liquid metal, and at the same time use the interaction between the laser and the liquid metal interface to induce nonlinear vibration of the liquid metal interface, so that the liquid metal diffuses directionally along the surface of the workpiece (22) and gradually wets into the defect area on the surface of the workpiece (22) to achieve wetting and replenishment. S4. During the spraying and laser processing, the excess liquid metal that does not adhere to the surface of the workpiece (22) during the processing is collected by the fixed component and then flowed back to the storage pump (15) through the recycling component to achieve recycling.

2. The laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates according to claim 1, characterized in that, In step S1, the fixing assembly includes a coarse filter membrane (10) and a fine filter membrane (9). The workpiece (22) is fixedly installed on the coarse filter membrane (10) by a clamp. The fine filter membrane (9) is located below the filter membrane. The coarse filter membrane (10) and the fine filter membrane (9) are both regulated by the main controller (6), the temperature control switch (4), and the temperature controller (3).

3. The laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates according to claim 2, characterized in that, In step S2, the high-pressure flow stabilizer nozzle (11) includes an air pump (12), a movable chamber (33), a high-pressure chamber (26), a low-pressure chamber (28), and a flow stabilizer (29) arranged in sequence. The air pump (12) is connected to the movable chamber (33) through an injection pump (24). A pressure piston (25) is slidably provided between the movable chamber (33) and the high-pressure chamber (26). The liquid storage pump (15) is connected to the high-pressure chamber (26) through an infusion switch (23). The high-pressure chamber (26) and the low-pressure chamber (28) are connected through an movable switch (32). The low-pressure chamber (28) is connected to the flow stabilizer (29) through a multi-channel nozzle (31). The injection pump (24), the infusion switch (23), and the movable switch (32) are all connected to the main control unit (6).

4. The laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates according to claim 3, characterized in that, When the liquid metal flows through the high-pressure chamber (26), the fluid resistance is reduced by the nanoscale hydrophobic coating on its inner wall; when it enters the low-pressure chamber (28), it undergoes preliminary rectification through the turbulence suppression grid at the inlet; and finally, it is stably ejected in a laminar flow manner by the multi-channel nozzle (31) and the flow stabilizer (29).

5. The laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates according to claim 4, characterized in that, In step S4, the coarse filter membrane (10) has a pore size of 50μm-100μm, the fine filter membrane (9) has a pore size of 5μm-10μm, and the surface is provided with an oleophobic and hydrophilic coating.

6. The laser-induced liquid metal wetting method for supplementing beryllium oxide ceramic substrates according to claim 5, characterized in that, In step S4, the recycling assembly includes a recycling chamber (8), a recycling pipe (7), and a recycling room (13). The top of the recycling chamber (8) is connected to the fine filter screen, and the bottom is connected to the recycling room (13) through the recycling pipe (7). The recycling room (13) is connected to the liquid storage pump (15).

7. The laser-induced liquid metal wetting method for supplementing a beryllium oxide ceramic substrate according to claim 6, characterized in that, The inner wall of the recycling pipe (7) is provided with a spiral guide groove, and the outer wall is provided with a heating layer.

8. The laser-induced liquid metal wetting method for supplementing a beryllium oxide ceramic substrate according to any one of claims 1 to 7, characterized in that, After the liquid metal is sprayed onto the workpiece (22), the coating detection device (2) emits a detection beam onto the surface of the workpiece (22) and receives the reflected light signal to determine the location of unevenness in the liquid metal coating. The coating detection device (2) converts the unevenness location information into an electrical signal and feeds it back to the laser modulator (17) so that the laser system is precisely aligned with the area. The nonlinear resonance effect generated by the laser guides the flow of the liquid metal, thereby achieving a smooth coating on the surface of the workpiece (22).

9. The laser-induced liquid metal wetting method for supplementing a beryllium oxide ceramic substrate according to claim 8, characterized in that, The liquid metal is liquid gallium (27), and the purity of the liquid gallium (27) is not less than 99%.

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